I've been waiting with bated breath for my text message/letter to come through telling me the end of my One Plan is nigh, and I'm still waiting. The only reason I've not ported out already is because I want to see what EE pull out of the hat in Jan/Feb (I'm assuming, like most people here, that they won't just let their SIM only tariff data allowances halve like they will according to the small print on their website).
I went to Kings Cross today on my lunch break, and Three's network was so congested I couldn't use any data at all. This morning, while waiting for the bus, I managed a paltry 0.4Mbps and struggled to refresh the bus times on my phone. Maybe Three are planning to wait until their network (hopefully) improves in Jan after the first lot of people loose their unlimited tethering, before asking One Plan users to pay more for the service? I'm a little skeptical whether this will happen though, as the 4G rollout hasn't done much to improve congestion (in London at least) despite my (overly optimistic?) hopes that it would. The way things are at the moment I wouldn't stay with Three even if they let me keep my £15/month One Plan - it's got to the point where I would rather just pay more for a service that works.
I use pretty much the average One Plan monthly data figures that have been posted on these forums, and would much rather pay £28/month to EE for a 10GB allowance than £25/month to Three for AYCE with the state their network is in at the moment. With cash back, the reality is the average One Plan user would be better off switching to EE on cost alone. The irony is that it's the heavy users who will find it harder to switch to EE, which are presumably the less profitable users for Three (though I realise heavy tethers might leave anyway since they can get more than 4GB tethered data elsewhere but not from Three). If the low to average One Plan users leave, and the heavy users end up staying (even with limited tethering), I can't imagine it would be a particularly good outcome for Three.